The Changes of T-Wave Amplitude and Tp-Te Interval in the Supine and Standing Electrocardiograms of Pediatric Postural Orthostatic Tachycardia Syndrome and Their Predictive Value for the Intervention Effect of Metoprolol

TL;DR

This study examines how T-wave amplitude and Tp-Te interval changes in ECGs of children with POTS predict the effectiveness of metoprolol treatment.

Contribution

The study identifies specific ECG changes in pediatric POTS patients that predict metoprolol treatment response.

Findings

Standing posture in POTS patients is associated with decreased T-wave amplitude and shortened Tp-Te interval in multiple ECG leads.

ΔT-wave amplitude in leads III, aVF, V2, V3, V4, and V5, along with ΔTp-Te interval and ΔTp-Te/QT ratio in lead V3, predict metoprolol treatment response.

ΔHR and ΔT-wave amplitude in lead V5 are independent risk factors for pediatric POTS.

Abstract

Objective: To investigate the changes in T-wave amplitude and Tp-Te interval on supine and standing electrocardiograms (ECGs) in pediatric postural orthostatic tachycardia syndrome (POTS), and to explore their predictive value for the therapeutic effect of metoprolol. Methods: A total of 59 children diagnosed with POTS who presented with syncope or pre-syncopal symptoms were enrolled as the POTS group, and 52 healthy children served as the control group. Supine and standing ECGs were recorded for all subjects, and T-wave amplitude and Tp-Te interval were measured. Children with POTS were followed-up after metoprolol treatment and divided into a therapeutic response group and a non-response group. Results: (1) Comparison of supine vs. standing ECGs: In the POTS group, standing posture (compared with supine posture) was associated with increased heart rate (HR), decreased T-wave amplitude in leads II, III, aVF, V4, V5, and V6, shortened Tp-Te interval in leads I, II, III, aVR, aVF, V1, V3, V4, V5, and V6, and elevated Tp-Te/QT ratio in leads aVL and V5 (all p < 0.05). (2) Comparison with the control group: The POTS group exhibited a greater HR difference (ΔHR), as well as larger differences in T-wave amplitude (ΔT-wave amplitude) between supine and standing positions in leads II, aVR, aVL, aVF, V3, and V5 (all p < 0.05). (3) Follow-up: Compared with the non-response group, the therapeutic response group showed larger ΔT-wave amplitude in leads III, aVF, V2, V3, V4, and V5, larger Tp-Te interval difference (ΔTp-Te interval) in lead V3, and larger Tp-Te/QT ratio difference (ΔTp-Te/QT ratio) in lead V3 (all p < 0.05). (4) Receiver operating characteristic curve: ΔT-wave amplitude in leads III, aVF, V2, V3, V4, and V5, ΔTp-Te interval in lead V3, and ΔTp-Te/QT ratio in lead V3 all had predictive value for the therapeutic effect of metoprolol in pediatric POTS (all p < 0.05). Conclusions: ΔHR and ΔT-wave amplitude in lead V5 between supine and standing positions are independent risk factors for pediatric POTS. A combination of five indicators—ΔT-wave amplitude in leads V2, V3, and V5, ΔTp-Te interval in lead V3, and ΔTp-Te/QT ratio in lead V3 between supine and standing ECGs—exerts a good predictive effect on the therapeutic response of pediatric POTS to metoprolol intervention.

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